Dev of Male and Female Repro Sys Flashcards
Urogential & Genital System
Unsegmented intermed mesoderm & mesonephric duct will become parts in male genital system.
Both come from intermediate mesoderm
*excretory mesonephric tubules will f shortly as nephrons; from unsegmented intermed mesoderm
Male Dev
Depents on SRY on Y chrom in order to develop as male
Identical to female until end of week 6
W/o SRY- will develop female
Gonads diff b/t sexes @ week 7
Primordial germ cells visible in 4th week among endoderm of yolk sac wall. Migrate to yolk sac via dorsal mesentary to genital ridges!
If germ cells fail to reach genital ridges in week 5= no further dev of testes/ovaries
Developing Gonad
Black= mesothelium
Brown= mesenchyme
Gonads form simply by prolif of mesothelium & condensation of mesenchyme underneath
Paramesonephric Ducts (Mullerian Duct)
Form by invagination of mesothelium
These are female ducts
*in orange* *not gonad but paramesonephric duct*
Primitive Sex Cords
Before primordial germ cell arrival
Epith of genital ridge prolif and penetrate into mesenchyme
Gonad is known as indifferent gonad!
SRY gene there= testis due to Testis Determining Factor protein TDF
If no SRY= ovary
Teste Development
Primitive sex cords prolif & penetrate deep into medulla to form medullary cords= will become rete testis & seminiferous tubules
Primordial germ cells= spermatogonia
Sertoli cells= from mesothelium
Interstial cells of Leydig= from mesenchye, active 8 weak-4 month & then quite until puberty
Ovary Development
Primitive Sex cords develop into medullary cords but then degen & replaced by ovarian Medulla
Week 7- corticol cords from mesothelium.
Month 4- cortical cords split to give follicles
Primordial Germ cells- oogonia
*no tunica albuginea
Genital Duct Dev
Week 6= indifferent stage
Both male & female embryos have:
- mesonephric/wolffian ducts (blue)
- paramesonephric/ mullerian ducts
Genital Ducts in Male
BLUE
- mesonephric duct (appendix epididymis, ductus deferens, ductus epididymis)
- excretory mesonephric tubules (ductuli efferentes, paradidymis)
ORANGE
- paramesonephric duct (appendix testis, prostatic utricle)
Other Embryological Structures
Seminiferous Tubules & Rete Testis= from primitive sex cords
Ductuli efferents= from excretory tubules (epigenital) of mesonephros
Ductus deferens & ductus epididymis= from mesonephric/wollfian duct
Vestigial structures in male= appendix epididymis (very cranial part of mesonephric ducts) & paradidymis (paragenital tubules) BLUE
= prostatic utricle & appendix testis ORANGE
**both appendices may become twisted; appendage torsion
Genital Ducts in Female
ORANGE
- paramesonephric ducts- oviducts, uterus, upper part of vagina
- if you want a vagina need the paramesonephric tubercle
BLUE
- remaining mesonephros: epoophoron, paroophoron, Gartner’s cyst
Primitive Urogenital Sinus & Vagina
Primitive urogenital sinus= urinary bladder & lower part of vagina
Primitive urogenital sinus & vagina 2
Origins of Vagina
Oviduct, uterus & upper vagina from paramesonephric duct
lower part from sinovaginal bulb/urogenital sinus
imperforate hymen= can be corrected surgically
In Males
Remnant Of Homolog To
Appendix Testis: cranial mullerian oviduct
Prostatic utricle: caudal mullerian uterus
Seminal colliculus: sinus tubercle hymen
All in ORANGE
In Females
Remanant of
Epoophoron: cranial mesonephric duct
Paraoophoron: some tubules
Gartner’s cyst: caudal part of mesonephric duct
*all in BLUE*
Homologues
Male prostate gland
Female urethral & paraurethral glands
Male bulbourethral glands
Female greater vesticular glads
Male seminal vesicls
No female homologue
Summary
Uterine & Vaginal Defects
External Genitalia
Indifferent stage= 6th week
Cloacl folds= fromed by mesenchyme cell migrating around cloacal mem
Cranially cloacal folds unite to form genital tubercle
Caudally cloacal folds subdivided into urethral folds and anal folds
Genital swellings appear at same time, later become scrotal swellings in male & labia majora in female
Male External Genitals
Androgen stimulates elongation of genital tubercle (phallus), contains glans & shaft of penis
Definitive urogenital sinus- penile urethra
Urethral fold- penis surrounding penile (spongy) urethra
Genital fold- scrotum
Male
Female External Genitals
Genital tubercle- clitoris
Definitive urogenital sinus- vestibule
Urethral fold- labia minora
Genital fold- labia majora
Imperforate Hymen
Hydrometrocolpos
